Capacity Retention Of Batteries Research Articles

Application Scopes of Miniaturized MXene-Functionalized Electrospun Nanofibers-Based Electrochemical Energy Devices.

Exploring combinatorial materials, as well as rational device configuration design, are assumed to be the key strategies for deploying versatile electrochemical devices. MXene sheets have revealed a high hydrophilic surface with proper mechanical and electrical characteristics, rendering them supreme additive candidates to integrate in electrospun electrochemical power tools. The synergetic effects of MXene 2D layers with the nanofibrous networks can boost actuator responsive ability, battery capacity retention, fuel cell stability, sensor sensitivity, and supercapacitor areal capacitance. Their superior mechanical features can be endowed to the electrospun layers through the embedding of the MXene additive. In this review, the preparation and inherent features of the MXene configurations are briefly evaluated. The fabrication and overall performance of the MXene-loaded nanofibers applicable in electrochemical actuators, batteries, fuel cells, sensors, and supercapacitors are comprehensively figured out. Eventually, an outlook on the future development of MXene-based electrospun composites is presented. A substantial focus has been devoted to date to engineering conjugated MXene and electrospun fibrous frames. The potential performance of the MXene-decorated nanofibers presents a bright future of nanoengineering toward technological growth. Meanwhile, a balance between the pros and cons of the synthesized MXene composite layers is worthwhile to consider in the future.

Sodium-rich prussian blue analogue coated by poly(3,4-ethylenedioxythiophene) polystyrene sulfonate as superior cathode for sodium-ion batteries

Sodium-ion batteries (SIBs) are a promising alternative to complement costly lithium-ion batteries for grid-scale stationary energy storage systems. However, finding a suitable cathode material has been a challenging process mainly due to the large radius of sodium-ion that hinders the process of intercalation. In our previous work, we have successfully synthesized Prussian blue analogue (PBA) via simple single iron source precipitation and low thermal method. However, it suffered poor electrical conductivity. In this work, the as-prepared PBA (high purity, low vacancy (∼2%), and high sodium-ion content) was then coated with various concentrations of conductive polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT-PSS) via simple stirring method to aid the electron route. The coated PBA (PB–P5) demonstrates two-fold enhanced conductivity of 2.04 × 10−5 S cm−1 at 30 °C and 1.18 × 10−4 S cm−1 at 100 °C. XRD peaks of coated PBAs show a slight shifting to higher diffraction angle, indicating the changes from rhombohedral-like to cubic structure. The battery capacity retention has also improved from 73.9% (PB–P0) to 82.87% (PB–P5), on account of having PEDOT-PSS to slow down the side reaction between cathode and electrolyte and eventually improve the cycling stability. Additionally, PB-P5 displays the lowest potential separation in cyclic voltammetry (CV) and small charge transfer resistance, Rct value, in which indicating a better electron transfer and enhanced overall conductivity.

Bifunctional mechanism and electrochemical performance of self-healing nitrile ether electrolyte additives in 4.5 V LiCoO2/artificial graphite lithium-ion batteries

To increase the lifespan, energy density, and temperature performance of LiCoO2/artificial graphite lithium-ion batteries (LCO/AG LIBs) to meet the requirements of 5G devices, three nitrile ether molecules are developed as bifunctional electrolyte additives to match 4.5 V LCO/AG LIBs. The commonalities and differences of these three nitrile ether molecules as additives are revealed. The batteries with nitrile ether additives can be cycled more than 1000 cycles at 4.5 V, 25 °C, and 1C, while the capacity retention of battery without additives after 200 cycles is close to 0%. At 45 °C, additive with four CN bonds can also lead to stable cycling over 600 cycles, whereas the batteries without additives fail after 100 cycles. It is demonstrated that nitrile ether additives participate in the repair and stabilization of interface films, which decreases the electrolyte decomposition. And the greater the number of CN bonds contained in the molecules, the stronger ability inhibits Co3+ dissolution from LCO, which is the main reason for the difference in the properties of the nitrile ether molecule. These results not only reveal the promising prospects of nitrile ether additives in practical applications but also provide a strategy to develop functional electrolytes for high voltage LCO/AG LIBs.

Hydrothermally synthesized MnSe as high cycle stability anode material for lithium-ion battery

Seeking for superior electrode materials is a significant project in lithium-ion battery research interests. In this paper, pure MnSe was synthesized via a simple hydrothermal method, which exhibits high crystalline and lamellar plate microstructure by systematical characterization analysis. Further, the as-synthesized MnSe was investigated for electrochemical performance as anode material of lithium-ion battery via correlative measurements. In the half-cell tests, the MnSe lithium-ion battery has delivered large specific capacity (302.7 mAh g−1 at 0.2 C), proper voltage platform, excellent rate performance, satisfactory reversibility, and outstanding ionic conductivity. It should be noted that the capacity retention of battery can reach up to 70.8% even after 3000 times cycle at 5.0 C current density, demonstrating remarkable cycle stability. This work not only reveals superior performance of MnSe materials from a different perspective but also provides a potential practical candidate for lithium-ion battery anode.

Bifunctional sandwich structure of vertically-oriented graphenes and boron nitride nanosheets for thermal management of LEDs and Li-ion battery

Efficient thermal management is a critical issue in the microelectronics. This work proposes a bifunctional sandwich structure composing of vertically-oriented graphenes (VGs) and boron nitride nanosheets (BNNSs) for thermal management of LEDs and lithium-ion (Li-ion) battery. VGs exploit the ultrahigh in-plane thermal conductivity of graphene for heat dissipation, meanwhile BNNSs suppress electron transfer for electrical insulation. Thermal and electrical property can be regulated by manipulating the morphology, which is further interpreted by Maxwell-Garnett’s effective medium approximation and finite element simulation. Especially, sandwich structure achieves superior thermal conductivity (∼4.03 W m−1 K−1, ∼19 times higher than that of polymer) and good electrical insulation (>107 Ω cm). Moreover, it exhibits a good thermal stability (up to 100 °C), extending the glass transition temperature to 119.7 °C. Infrared thermal imaging technology suggests that heating-up rate of composite is over ∼4 times higher than that of polymer. During the practical thermal management, sandwich structure can effectively decrease the operating temperature of LEDs and Li-ion battery by ∼16.6 °C and ∼10 °C, respectively. As such, capacity retention of battery is remarkably improved by ∼22.2% during the charging/discharging process. This strategy may open a new avenue of designing sandwich structure for efficient thermal management.

The Study of How the Amount of Adiponitrile Impacts on the Performance of LiNi0.5Mn1.5O4 Battery

Adiponitrile (ADN) has been applied into the lithium ion battery as an additive. However, how the amount of ADN impacts on the cycle and interface property of LiNi0.5Mn1.5O4 is still unknown. In this work, we put different amount of ADN (0.5wt%, 1.0wt%, 2.0wt%, 5.0wt% and 10.0wt%) into the 1 M LiPF6-EC/DMC/EMC (1:1:1 by weight) to explore its effect and mechanism. The results of measurements show that the capacity retention of battery with 0.5% ADN has the highest value of 97.1% (126.3 mAh/g) at 0.1C after 50 cycles. While other systems’ capacity drops down with the cycles obviously. Especially, when the amount of ADN increases, the polarization becomes serous and there occurs the dark passive film between particles. To explain why this situation happens, we carry out the XPS measurement and analog computation. Combining with these results, we draw a conclusion that as the amount increases, different groups such as (ADN+H) and (ADN-H) are produced and these groups can continue to participate in the film-forming reaction, which is responsible for the poor capacity and passive film.

Sodium Alginate: A Water-Processable Binder in High-Voltage Cathode Formulations

Binders are electrochemically inactive electrode components. However, their chemical and physical nature greatly affects battery performance and plays a key role in electrode integrity and interface reactivity. The binders thus have a strong impact on battery capacity retention and cycle life. Water-processable binders would make the electrode preparation process cheap and environmentally friendly and provide a viable alternative to polyvinylidene difluoride (PVdF). Here we report the use of sodium alginate (SA) as binder for LiNi0.5Mn1.5O4 (LNMO), one of the most promising cathode materials for high-voltage and high-energy LIBs. We demonstrate that electrodes with high mass loading containing SA have excellent specific discharge capacity (120 mAh g−1 at C/3 and 100 mAh g−1 at 5C) with negligible overpotentials in conventional electrolyte based on ethylene carbonate (EC): dimethyl carbonate (DMC) and 1 M LiPF6, where the reactivity of LNMO is known to negatively affect stability. The electrodes with SA also show a good stability over subsequent cycles of charge and discharge at 1C with capacity retention of 95% and 86% with respect to the initial cycles at the 100th and 200th cycle.

Deformation of Lithium-Ion Battery Anodes during SEI Formation: a Probe for the Structure of the SEI

Lithium-ion batteries are ubiquitous in small, portable electronics, where the lifetime of the battery now exceeds the expected lifetime of the device (ca. 2 years). Capacity fade over time, however, remains a significant challenge hindering the use of lithium-ion batteries in more demanding applications with long life-time requirements, such as in electric vehicles. One of the primary contributors to capacity fade is lithium trapping within the solid-electrolyte interphase (SEI) on the anode, making understanding the SEI critical to the design of more reliable lithium-ion batteries. The size-scale (tens of nanometers) and reactivity of the SEI, though, make characterization of the SEI difficult. In this presentation, we present a new method to probe the structure of the SEI that is formed on lithium-ion battery anodes. A custom battery cell employs an unconstrained (i.e. not on a current collector) graphite composite electrode and allows optical access to the electrode during electrochemical cycling. Electrolyte is reduced on the electrode surface potentiostatically, and the resulting deformation of the electrode is measured using digital image correlation (DIC), an optical, full-field strain measurement technique. The amount of deformation of the electrode induced during SEI formation is related to the structure of the SEI layer. The strain measurements are then compared to galvanostatic cycling results, and the effects of different electrolyte salts, solvents, and additives on the SEI structure and battery capacity retention are evaluated. Figure 1

Cu3P as anode material for lithium ion battery: powder morphology and electrochemical performances

Cu3P is studied as a potential material to be used as anode in a Li-ion battery. Depending on the synthetic route, solvothermal, ball-milling (with or without annealing), spray method or ceramic, used for its preparation, Cu3P shows various particle sizes and crystallinities. The electrochemical reactivity towards lithium of these various Cu3P powders is discussed through galvanostatic and potentiodynamic measurements, electron microscopy techniques, and X-ray diffraction on powder. Electrochemical performances, especially initial capacity and capacity retention, are shown to strongly correlate to the powder morphologies: small particle size favors high capacity values and the operation scan rate affects the capacity depending on the degree of crystallinity of the powder. On other hand, the battery capacity retention is better with microsized powders.